Medical grafting connectors and fasteners

ABSTRACT

A body tissue graft for use in a patient includes a frame structure made of a first elastic material, a covering of a second elastic material on the frame structure, the covering substantially filling openings in the frame structure, and a connector connected to the frame structure. Projections are secured to the connector structure. The projections facilitate attachment of the tubular graft in a patient by securing the graft to the body tissue with which the graft is employed. The connector selectively circumferentially expands and the projections selectively circumferentially expand. This may be done using an inflatable balloon to circumferentially expand the projections. A restraining member may be provided to restrain the projections in a cone shape so that an end of the graft may be used to open an aperture through a side wall of existing body organ tubing and a portion of the projections may enter the aperture.

[0001] This is a continuation of application Ser. No. 08/839,199, filedApr. 23, 1997, which is hereby incorporated by reference herein in itsentirety.

BACKGROUND OF THE INVENTION

[0002] This invention relates to medical grafting methods and apparatus,and more particularly to methods and apparatus for connecting orfastening tubular bypass grafts.

[0003] An example of the possible uses of the invention is a minimallyinvasive cardiac bypass procedure. This example will be considered indetail, but it will be understood that various aspects of the inventionhave many other possible uses.

[0004] Several procedures are known for revascularizing the human heartin order to treat a patient with one or more occluded coronary arteries.The earliest of these procedures to be developed involves exposing theheart by means of a midline sternotomy. Following surgical exposure ofthe heart, the patient's aorta and vena cava are connected to aheart/lung machine to sustain vital functions during the procedure. Thebeating of the heart is stopped to facilitate performance of theprocedure. Typically, a suitable blood vessel such as a length of thepatient's saphenous (leg) vein is harvested for use as a graft. Thegraft is used to create a new, uninterrupted channel between a bloodsource, such as the aorta, and the occluded coronary artery or arteriesdownstream from the arterial occlusion or occlusions. A variation of theabove procedure involves relocating a mammary artery of the patient to acoronary artery.

[0005] Although the above-described sternotomy procedures areincreasingly successful, the high degree of invasiveness of theseprocedures and the requirement of these procedures for generalanesthesia are significant disadvantages. Indeed, these disadvantagespreclude use of sternotomy procedures on many patients.

[0006] More recently, less invasive procedures have been developed forrevascularizing the heart. An example of these procedures is known asthoracostomy, which involves surgical creation of ports in the patient'schest to obtain access to the thoracic cavity. Specially designedinstruments are inserted through the ports to allow the surgeon torevascularize the heart without the trauma of a midline sternotomy.Drugs may be administered to the patient to slow the heart during theprocedure. Some thoracostomy procedures involve relocating a mammaryartery to a coronary artery to provide a bypass around an occlusion inthe coronary artery.

[0007] Thoracostomy bypass procedures are less traumatic than sternotomybypass procedures, but they are still too traumatic for some patients.Also, the number of required bypasses may exceed the number of mammaryarteries, thereby rendering thoracostomy procedures inadequate to fullytreat many patients.

[0008] Another technique for revascularizing the human heart involvesgaining access to the thoracic cavity by making incisions between thepatient's ribs. This procedure is known as thoracotomy. It is alsosubstantially less traumatic than midline sternotomy, but it is stilltoo traumatic for some patients.

[0009] In view of the foregoing, even less traumatic approaches havebeen developed for revascularizing a patient, as described in Goldsteenet al. U.S. patent application Ser. No. 08/745,618, filed Nov. 7, 1996,and hereby incorporated by reference herein in its entirety. With suchapproaches, a graft (e.g., of saphenous vein) can be delivered to anoperative site in the patient through the patient's existing arteriesand veins. The graft is typically inserted between two attachment sitesin the patient's existing body organs (e.g., between a site along thepatient's aorta and a site along the coronary artery downstream from acoronary artery occlusion).

[0010] Thus the above-mentioned Goldsteen et al. reference shows, amongother things, methods and apparatus for installing tubular bypass graftsintralumenally. The Goldsteen et al. reference shows methods andapparatus in which each end of the graft site is approached separatelyand intralumenally, penetrated, and then a longitudinal structure (e.g.,element 150 in the Goldsteen et al. reference) is established betweenthe ends of the graft site. This longitudinal structure may extendintralumenally all the way out of the patient's body from both ends ofthe graft site. The graft is fed into the patient's body intralumenallyalong the longitudinal structure until it is in the desired positionextending from one end of the graft site to the other. Each end of thegraft is then secured at a respective end of the graft site and thelongitudinal structure is withdrawn from the patient.

[0011] Tubular artificial grafts are needed in various medicalprocedures. For example, such grafts may be needed to replace diseasedor damaged sections of natural tubular body tissue such as in thecirculatory system, the urinary tract, etc. Or such grafts may be neededto make new connections in natural tubular body tissue systems such asbypass or shunt connections in the circulatory system. In general, anartificial tubular graft may be needed as either a temporary orpermanent installation.

[0012] Important considerations regarding the use of artificial graftsinclude ease of use, time required for installation, secureness ofinstallation, and performance after installation. Improvements areconstantly sought in all of these areas.

[0013] It is therefore an object of this invention to provide improvedgrafts.

[0014] It is therefore a further object of this invention to provideimproved methods and apparatus for the connection of grafts, whethernatural or artificial.

[0015] It is therefore a further object of the invention to provideimproved graft structures for use in the repair, replacement, orsupplementing of natural body organ structures or tissues, and toprovide methods and apparatus for fastening or connecting such graftstructures.

[0016] It is therefore a further object of this invention to provideimproved methods and apparatus for installing medical grafts, whethernatural or artificial.

SUMMARY OF THE INVENTION

[0017] This and other objects of the invention are accomplished inaccordance with the principles of the invention by providing apparatusfor use as a body tissue graft and methods for securing the graft in apatient comprising a frame structure made of a first elastic material, acovering of a second elastic material on the frame structure, thecovering substantially filling openings in the frame structure, and aconnector connected to the frame structure. Projections are secured tothe connector structure. The projections facilitate attachment of thetubular graft in a patient by securing the graft to the body tissue withwhich the graft is employed. The connector selectively circumferentiallyexpands and the projections selectively circumferentially expand. Thismay be done using an inflatable balloon to circumferentially expand theprojections and the connector. A restraining member may be provided torestrain the projections in a cone shape so that an end of the graft maybe used to open an aperture through a side wall of existing body organtubing and a portion of the projections may enter the aperture. Theconnector structures of this invention may be used with artificialgrafts having any construction (i.e., other than the frame-and-coveringconstruction mentioned above), and they may also be used with naturalbody tissue grafts.

[0018] Further features of the invention, its nature, and variousadvantages will be more apparent from the accompanying drawings and thefollowing detailed description of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a simplified longitudinal sectional view showing aportion of an illustrative procedure and related apparatus in accordancewith this invention.

[0020]FIG. 2 is a simplified longitudinal sectional view showing aportion of a more particular illustrative procedure and relatedapparatus in accordance with the invention.

[0021]FIG. 3 is a simplified longitudinal sectional view showing anillustrative embodiment of a portion of the FIG. 2 apparatus in moredetail.

[0022]FIG. 4 is a view similar to FIG. 2 showing a later stage in theillustrative procedure depicted in part by FIG. 2, together with relatedapparatus, all in accordance with this invention.

[0023]FIG. 5 shows an even later stage in the illustrative proceduredepicted in part by FIG. 4, together with related apparatus, all inaccordance with this invention.

[0024]FIG. 6 is a view similar to FIG. 4 showing a still later stage inthe illustrative procedure depicted in part by FIG. 5.

[0025]FIG. 7 is a simplified longitudinal sectional view of anillustrative embodiment of a portion of an illustrative apparatus inaccordance with this invention.

[0026]FIG. 8 is a simplified elevational view of an illustrativeembodiment of one component of the FIG. 7 apparatus.

[0027] FIG., 9 is a simplified longitudinal sectional view of anillustrative embodiment of another portion of the FIG. 7 apparatus.

[0028]FIG. 10 is a view similar to a portion of FIG. 6 showing an evenlater stage in the illustrative procedure depicted in part by FIG. 6.

[0029]FIG. 11 is a view similar to FIG. 10 showing a still later stagein the FIG. 10 procedure.

[0030]FIG. 12 is a view similar to FIG. 11 showing an even later stagein the FIG. 11 procedure.

[0031]FIG. 13 is a view similar to another portion of FIG. 6 showing astill later stage in the FIG. 12 procedure.

[0032]FIG. 14 is a view similar to FIG. 13 showing an even later stagein the FIG. 13 procedure.

[0033]FIG. 14a is a view similar to FIG. 14 showing a still later stagein the FIG. 14 procedure.

[0034]FIG. 14b is a view similar to FIG. 14a showing an even later stagein the FIG. 14a procedure.

[0035]FIG. 15 is a view similar to FIG. 14b showing a still later stagein the FIG. 14b procedure.

[0036]FIG. 16 is a view similar to FIG. 15 showing an even later stagein the FIG. 15 procedure.

[0037]FIG. 17 is a simplified longitudinal sectional view of anillustrative embodiment of a portion of more apparatus in accordancewith this invention.

[0038]FIG. 18 is a view similar to FIG. 12 showing a later stage in theFIG. 16 procedure.

[0039]FIG. 19 is a view similar to FIG. 18 showing a still later stagein the FIG. 18 procedure.

[0040]FIG. 20 is a view similar to FIG. 16 showing an even later stagein the FIG. 19 procedure.

[0041]FIG. 21 is a view similar to FIG. 20 showing a still later stagein the FIG. 20 procedure.

[0042]FIG. 22 is a view similar to FIG. 21 showing an even later stagein the FIG. 21 procedure.

[0043]FIG. 23 is a view similar to FIG. 6 showing the end result of theprocedure depicted in part by FIG. 22.

[0044]FIG. 24 is a simplified longitudinal sectional view showing an endresult similar to FIG. 23 but in a different context.

[0045]FIG. 25 is a simplified elevational view (partly in section)showing another possible alternative construction of portions of theFIG. 7 apparatus.

[0046]FIG. 26 is a simplified longitudinal sectional view of the FIG. 25apparatus in another operating condition.

[0047]FIG. 26a is a simplified elevational view (partly in section)showing another possible alternative construction of portions of theFIG. 7 apparatus.

[0048]FIG. 26b is a simplified elevational view of an illustrativeembodiment of one component of the apparatus shown in FIG. 26a.

[0049]FIG. 27 is a simplified end view of an illustrative embodiment ofa component of the graft shown in FIGS. 25 and 26.

[0050]FIG. 28 is an elevational view of a structure that can be used tomake a particular embodiment of the apparatus portion shown in FIG. 27.

[0051]FIG. 29 is a simplified elevational view of a subsequent conditionof the FIG. 28 structure during fabrication.

[0052]FIG. 29a is a simplified enlargement of a portion of FIG. 29 withother components added.

[0053]FIG. 30 is a simplified longitudinal sectional view showinganother possible alternative construction of portions of the apparatusshown in FIG. 7.

[0054]FIG. 30a is a simplified longitudinal sectional view showing stillanother possible alternative construction of portions of the apparatusshown in FIG. 7.

[0055]FIG. 31 is a simplified longitudinal sectional view showing yetanother possible alternative construction of portions of the apparatusshown in FIG. 7.

[0056]FIG. 32 is a simplified longitudinal sectional view showing stillanother possible alternative construction of portions of the apparatusshown in FIG. 7.

[0057]FIG. 33 is a view similar to FIG. 13 showing an alternativeillustrative embodiment of certain components.

[0058]FIG. 34 is a view similar to a portion of FIG. 16 for thealternative embodiment shown in FIG. 33.

[0059]FIG. 34a is another view similar to FIG. 34 showing anotheralternative illustrative embodiment of the invention.

[0060]FIG. 34b is an elevational view taken from the right in FIG. 34a.

[0061]FIG. 35 is a simplified elevational view of apparatus which can beused as an alternative to certain apparatus components shown in FIG. 7.

[0062]FIG. 36 is a view similar to a composite of FIGS. 7 and 9 showinganother alternative illustrative embodiment of certain aspects of theinvention.

[0063]FIG. 37 is a simplified elevational view showing anotherillustrative embodiment of an artificial graft constructed in accordancewith the invention.

[0064]FIG. 38 is another view similar to FIG. 37 showing anotheroperating condition of the FIG. 37 graft.

[0065]FIG. 39 is another view similar to FIG. 37 showing the graft beinginstalled in tubular body tissue.

[0066]FIG. 40 is another view similar to FIG. 39 showing a later stagein the installation of the graft.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0067] Because the present invention has a number of differentapplications, each of which may warrant some modifications of suchparameters as instrument size and shape, it is believed best to describecertain aspects of the invention with reference to relatively genericschematic drawings. To keep the discussion from becoming too abstract,however, and as an aid to better comprehension and appreciation of theinvention, references will frequently be made to specific uses of theinvention. Most often these references will be to use of the inventionto provide a bypass around an occlusion or obstruction (genericallyreferred to as a narrowing) in a patient's coronary artery, and inparticular a bypass from the aorta to a point along the coronary arterywhich is downstream from the coronary artery narrowing. It is emphasizedagain, however, that this is only one of many possible applications ofthe invention.

[0068] Assuming that the invention is to be used to provide a bypassfrom the aorta around a coronary artery narrowing, the procedure maybegin by inserting an elongated instrument into the patient'scirculatory system so that a distal portion of the instrument extendsthrough the coronary artery narrowing to the vicinity of the point alongthe artery at which it is desired to make the bypass connection. This isillustrated by FIG. 1, which shows elongated instrument 100 entering thepatient's circulatory system 10 at a remote location 12 and passingcoaxially along vessels in the circulatory system until its distal endportion 104 passes through narrowing 22 in coronary artery 20 andreaches the downstream portion 24 of the artery to which it is desiredto make a bypass connection. For example, the entry location 12 ofinstrument 100 may be a femoral (leg) artery of the patient, a brachialartery of the patient, or any other suitable entry point. It will beappreciated, however, that entry point 12 is typically remote from thelocation at which the bypass is to be provided, and that control ofinstrument 100 throughout its use is from the proximal portion 102 thatis outside the patient at all times.

[0069] For the illustrative procedure being discussed, FIG. 2 shows apreferred embodiment of instrument 100 in more detail. As shown in FIG.2, instrument 100 may include a catheter tube 110 which is inserted(from location 12 in FIG. 1) via the patient's aorta 30 to the ostium ofcoronary artery 20. Another tubular structure 120 is then extended fromthe distal end of catheter 110, through narrowing 22 to location 24.

[0070] An illustrative construction of tubular structure 120 is shown inmore detail in FIG. 3. There it will be seen that structure 120 may havetwo lumens 130 and 140. Near the distal end of structure 120, lumen 130communicates with the interior of an inflatable balloon 132 on one sideof structure 120, while lumen 140 opens out to the opposite side ofstructure 120. Lumen 140 contains a longitudinal structure 150 which maybe a stylet wire with a sharpened distal tip 152. Structure 120 may beprovided with a distal spring tip 122 to help guide the distal end ofstructure 120 along coronary artery 20 and through narrowing 22. Asafety ribbon 123 (e.g., of the same material as tip 122) may beconnected at its proximal end to the distal end of member 120 and at itsdistal end to the distal end of tip 122 to improve the performance oftip 122 and to help prevent separation of any portion of tip 122 fromstructure 120 in the event of damage to tip 122. Structure 120 may haveradiologic (e.g., radio-opaque or fluoroscopically viewable) markers 124at suitable locations to help the physician place the structure wheredesired in the patient's body. Catheter 110 may also have radiologicmarkers 112 for similar use. Balloon 132 is initially deflated.Longitudinal structure 150 is initially retracted within lumen 140.However, the distal portion of lumen 140 is shaped (as indicated at 142in FIG. 2) to help guide the distal tip 152 of structure 150 out to theside of structure 120 when structure 150 is pushed distally relative tostructure 120. This is discussed in more detail below. As earlierdescription suggests, each of components 110, 120, and 150 is separatelycontrollable from outside the patient, generally indicated as region 102in FIG. 1.

[0071] After instrument 100 is positioned as shown in FIGS. 1 and 2, asecond elongated instrument 200 is similarly introduced into thepatient's circulatory system 10. For example, instrument 200 may enterthe patient via a,femoral artery, a brachial artery, or any othersuitable location, which again is typically remote from the bypass site.If one femoral artery is used to receive instrument 100, the otherfemoral artery may be used to receive instrument 200. Or the samefemoral artery may be used to receive both instruments. Or any othercombination of entry points may be used for the two instruments.Instrument 200 is inserted until its distal end is adjacent to the point34 in the circulatory system which it is desired to connect to point 24via a bypass. This is illustrated in FIG. 4 where the distal end ofinstrument 200 is shown at location 34 in aorta 30. The particularlocation 34 chosen in FIG. 4 is only illustrative, and any otherlocation along aorta 30 may be selected instead. Radiologic markers 206may be provided on the distal portion of instrument 200 to help thephysician position the instrument where desired. Note that FIG. 4 showsportions of instruments 100 and 200 side by side in aorta 30.

[0072] The next step in the illustrative procedure being described ispreferably to deploy a snare loop 354 (FIG. 5) from the distal end 204of instrument 200 through the aorta wall to a location outside thecoronary artery wall adjacent coronary artery portion 24. This isexplained in more detail in the above-mentioned Goldsteen et al.reference. (Alternatively, this step could be performed somewhat later.)Then stylet wire 150 is moved in the distal direction so that its distaltip 152 passes through the wall of the coronary artery. As was mentionedearlier, the distal end of the stylet wire lumen in tube 120 is shapedto help guide stylet wire 150 through the coronary artery wall.

[0073] Once wire 150 is through snare loop 354, snare sheath or lumen340 is moved distally relative to the snare loop as shown in FIG. 5.This causes snare loop 354 to close down on wire 150. Snare sheath orlumen 340 also tends to trap the distal portion of wire 150 and to foldthat wire portion back on itself inside sheath or lumen 340. Thelongitudinal structures 150 and 350 are securely interengaged insidesnare sheath or lumen 340. The next step is to pull snare wire 352 inthe proximal direction all the way out of the patient. Because of theinterengagement between wires 150 and 352, withdrawing wire 352 pulls asmuch additional wire 150 into the patient from external location 102(FIG. 1). When wire 352 has been completely removed from the patient,there is then one continuous wire 150 from outside the patient at 102,through the patient, to outside the patient again. Wire 150 can now bemoved in either longitudinal direction through the patient. This wire oranother wire could be used to help pull various apparatus into thepatient via the tube or tubes through which the wire passes.

[0074] After one continuous wire 150 has been established through thepatient as described above, the other snare components such as 340 maybe withdrawn from the patient by pulling them proximally out of catheter210. The condition of the apparatus inside the patient is now as shownin FIG. 6. Note that the presence of fixed outlets for the wire from thedistal portion of tube 120 and the distal end of catheter 210 preventswire 150 from cutting tissues 20 and 30 when the wire is pulled ineither longitudinal direction. The portion of wire 150 extending throughthe interior of the patient between elements 120 and 210 may haveradiologic markers 154 equally spaced along its length. These can beviewed radiologically by the physician to determine the distance betweenregions 24 and 34 via wire 150. This helps the physician select thecorrect length of graft needed between regions 24 and 34.

[0075] The next phase of the illustrative procedure being described isto install a new length of tubing or graft between regions 24 and 34.The new length of tubing may be either an artificial graft, natural bodyorgan tubing harvested from the patient's body, or a combination ofartificial and natural tubing (e.g., natural tubing coaxially insideartificial tubing). In the following discussion it is assumed that thenew tubing is to be natural tubing (e.g., a length of the patient'ssaphenous vein that has been harvested for this purpose) inside anartificial conduit. When such a combination of natural and artificialconduits is used, both conduits can be delivered and installedsimultaneously, or the outer artificial conduit can be delivered andinstalled first, and then the inner natural conduit can be delivered andinstalled. The following discussion initially assumes that the lattertechnique is employed.

[0076] An illustrative embodiment of an artificial graft 430 is shown inFIG. 8. Although any suitable construction can be used for the mainportion of graft 430, a particularly preferred construction is shown anddescribed in the above-mentioned Goldsteen et al. reference. Forexample, this graft construction may include a tubular mesh framework432 of nitinol covered with silicone 434 to substantially fill in theinterstices in the framework. Additional details, features, andalternatives regarding this type of graft construction will be found inthe above-mentioned Goldsteen et al. reference, and in PCT publicationWO98/19632, which is also hereby incorporated by reference herein in itsentirety. Grafts having this type of construction are extremely elasticand they can be radically deformed without damage or permanent change inshape. For example, a graft of this construction can be stretched to asmall fraction of its original diameter, and it thereafter returns byitself to its original size and shape without damage or permanentdeformation of any kind. Grafts of this type can be made with anydesired porosity (e.g., through the silicone). For use in thecirculatory system, they can also be made so that they pulse in responseto pressure pulses in the blood flowing through them, very much like thepulsation of natural blood vessels. This can be important todiscouraging the formation of clots in the graft.

[0077] In accordance with the above-stated assumptions, the next step inthe procedure is to use catheter 210 and wire 150 to deliver anartificial conduit such as graft 430 so that it extends between regions24 and 34. The distal portion of an illustrative assembly 400 for doingthis is shown in FIG. 7. As shown in FIG. 7 assembly 400 includes athreaded, conical, distal tip 412 mounted on a tubular member 410 (e.g.,metal hypotube) through which wire 150 can freely pass. It should bementioned here that in this embodiment tip 412 is selectivelycollapsible to facilitate its withdrawal from the patient after it hasserved its purpose. Another tubular member 420 is disposedconcentrically around tubular member 410. An inflatable balloon 422 ismounted on the distal end of tubular member 420. Tubular member 420includes an axially extending lumen (not shown in FIG. 7) for use inselectively inflating and deflating balloon 422. Balloon 422 is showndeflated in FIG. 7.

[0078] Coaxially around tubular member 420 is artificial graft conduit430. As has been mentioned, an illustrative embodiment of a suitablegraft conduit 430 is shown in FIG. 8 and includes a tube formed of aframe 432 of a first highly elastic material (such as nitinol) with acovering 434 of a second highly elastic material (e.g., a rubber-likematerial such as silicone) substantially filling the apertures in theframe. At its distal end, extensions of frame 432 are flared out to formresilient struts 436. The struts 436 may have hooks and/or barbsdisposed thereon. Near the proximal end of conduit 430 two axiallyspaced resilient flaps 438 a and 438 b with prongs 439 are provided.

[0079] In assembly 400 (see again FIG. 7, and also FIG. 9), struts 436and flaps 438 are compressed radially inwardly and confined withinconduit delivery tube 440, which coaxially surrounds conduit 430.Indeed, conduit 430 may be somewhat circumferentially compressed by tube440.

[0080] The portion of assembly 440 at which the proximal end of conduit430 is located is shown in FIG. 9. There it will be seen how flaps 438are confined within conduit delivery tube 440. FIG. 9 also shows howtubes 410, 420, and 440 extend proximally (to the right as viewed inFIG. 9) from the proximal end of conduit 430 so that the physician canremotely control the distal portion of assembly 400 from outside thepatient.

[0081] To install artificial graft conduit 430 in the patient betweenregions 24 and 34, assembly 400 is fed into the patient along wire 150through catheter 210. When tip 412 reaches coronary artery portion 24,tip 412 is threaded into and through the coronary artery wall byrotating tube 410 and therefore tip 412. (Tube 120 may be pulled backslightly at this time to make sure that it does not obstruct tip 412.)The passage of tip 412 through the coronary artery wall opens up theaperture in that wall. After tip 412 passes through the artery wall,that wall seals itself against the outside of the distal portion ofconduit delivery tube 440 as shown in FIG. 10.

[0082] The next step is to push tube 410 and tip 412 distally relativeto delivery tube 440, which is held stationary. Conduit 430 is initiallymoved distally with components 410 and 412. This may be done byinflating balloon 422 so that it engages conduit 430, and then movingtube 420 distally with components 410 and 412. Distal motion of conduit430 moves struts 436 beyond the distal end of delivery tube 440, therebyallowing the struts 436 to spring out inside coronary artery 20 as shownin FIG. 11. This prevents the distal end of conduit 430 from beingpulled proximally out of the coronary artery. If balloon 422 wasinflated during this phase of the procedure, it may be deflated beforebeginning the next phase.

[0083] The next step is to pull delivery tube 440 back slightly so thatit is withdrawn from coronary artery 20. Then tube 420 is moved distallyso that balloon 422 is radially inside the annulus of struts 436.Balloon 442 is then inflated to ensure that struts 436 (and barbs and/orhooks if provided) are firmly set in coronary artery 20. Conditions arenow as shown in FIG. 12. Cross sections of balloon 422 may be L-shapedwhen inflated (one leg of the L extending parallel to the longitudinalaxis of conduit 430, and the other leg of the L extending radiallyoutward from that longitudinal axis immediately distal of struts 436).This may further help to ensure that struts 436 fully engage the wall ofcoronary artery 20.

[0084] The next step is to deflate balloon 422. Then delivery tube 440is withdrawn proximally until flap 438 a (but not flap 438 b) is distalof the distal end of the delivery tube. This allows flap 438 a to springradially out as shown in FIG. 13. Tube 420 is then withdrawn untilballoon 422 is just distal of flap 438 a. Then balloon 422 is inflated,producing the condition shown in FIG. 13.

[0085] The next steps are (1) to deflate distal balloon 214, (2) toproximally withdraw catheter 210 a short way, (3) to proximally withdrawtube 420 to press flap 438 a against the outer surface of the aortawall, and (4) to proximally withdraw delivery tube 440 by the amountrequired to allow flap 438 b to spring out against the interior ofcatheter 210, all as shown in FIG. 14. As a result of theabove-described proximal withdrawal of tube 420, the prongs 439 on flap438 a are urged to enter the aorta wall tissue to help maintainengagement between flap 438 a and the wall of the aorta. Inflatedballoon 422 helps to set prongs 439 in the tissue when tube 420 istugged proximally.

[0086] The next step is to insert the distal portion of delivery tube440 into the proximal end of conduit 430 as shown in FIG. 14a. Thedistal end of conduit 430 may be inserted all the way to the proximalend of balloon 422 (see FIG. 15 for a depiction of this). A purpose ofthis step is to subsequently help control the rate at which blood isallowed to begin to flow through conduit 430.

[0087] The next step is to proximally withdraw catheter 210 by theamount required to release flap 438 b to spring out against the interiorof the wall of aorta 30 as shown in FIG. 14b. Catheter 210 may besubsequently pushed back against flap 438 b as shown in FIG. 15 to helpsecurely engage that flap against the aorta wall.

[0088] Artificial graft conduit 430 is now fully established betweenaorta region 34 and coronary artery region 24. The next steps aretherefore to deflate balloon 422 and proximally withdraw tube 420, tocollapse tip 412 and proximally withdraw tube 410, and to proximallywithdraw delivery tube 440. The proximal end of conduit 430 is now asshown in FIG. 16. As possible alternatives to what is shown in FIG. 16,the distal end of catheter 210 could be left pressed up against proximalflap 438 b and/or the distal portion of delivery tube 440 could be leftinside the proximal portion of conduit 430. If the latter possibility isemployed, then delivery of the natural graft conduit (described below)can be through tube 440.

[0089] As has been mentioned, the illustrative procedure being describedassumes that natural body conduit (e.g. a length of the patient'ssaphenous vein that has been harvested for this purpose) is installedinside artificial conduit 430 after installation of the latter conduit.An illustrative assembly 500 for delivering a length of natural bodyconduit to installed conduit 430 is shown in FIG. 17.

[0090] As shown in FIG. 17, assembly 500 includes a tube 510 disposedaround wire 150 so that tube 510 is freely movable in either directionalong wire 150. Tube 510 has an inflatable annular balloon 512 a nearits distal end and another inflatable annular balloon 512 b spaced inthe proximal direction from balloon 512 a. Tube 510 includes separateinflation lumens (not shown) for each of balloons 512 so that theballoons can be separately inflated and deflated. An annular collarstructure or ring 520 a is disposed concentrically around balloon 512 a,and a similar annular collar structure or ring 520 b is disposedconcentrically around balloon 512 b. Balloons 512 may be partlyinflated. Each of rings 520 may have radially outwardly extending prongs522. The rings 520 may alternatively or additionally be fluted orprovided with raised portions (alternatives that are discussed below(e.g., in connection with FIGS. 27-29 a and 36)). A length of naturalbody conduit 530 (e.g., saphenous vein as mentioned earlier) extendsfrom ring 520a to ring 520 b around the intervening portion of tube 510.Prongs 522 may extend through the portions of conduit 530 that axiallyoverlap rings 520. A delivery tube 540 is disposed around conduit 530.In use, tubes 510 and 540 extend proximally (to the right as viewed inFIG. 17) out of the patient to permit the physician to remotely controlthe distal portion of assembly 500.

[0091] Instead of prongs 522, the rings 520 may be provided with flutedor raised structures that grip the graft conduit 430. Instead ofballoons 512 being both on the same tube 510, balloon 512 a may be on arelatively small first tube, while balloon 512 b is on a larger secondtube that concentrically surrounds the proximal portion of the firsttube. The first and second tubes are axially movable relative to oneanother, thereby allowing the distance between balloons 512 to beadjusted for grafts 530 of different lengths. An illustrative apparatusof this kind is shown in Goldsteen et al. U.S. patent application Ser.No. 08/839,298, filed Apr. 17, 1997, which is hereby incorporated byreference herein.

[0092] Assembly 500 is employed by placing it on wire 150 leading intocatheter 210. Assembly 500 is then advanced distally along wire 150through catheter 210 and then into conduit 430 until the distal end ofconduit 530 is adjacent the distal end of conduit 430 and the proximalend of conduit 530 is adjacent the proximal end of conduit 430. Thecondition of the apparatus at the distal end of assembly 500 is now asshown in FIG. 18. The condition of the apparatus at the proximal end ofconduit 530 is as shown in FIG. 20.

[0093] The next step is to proximally withdraw delivery tube 540 so thatthe distal portion of conduit 530 and distal ring 520 a are no longerinside the distal portion of delivery tube 540. Then distal balloon 512a is inflated to circumferentially expand ring 520 a and to set prongs522 through conduit 530 into the surrounding portion of conduit 430 andcoronary artery wall portion 24. This provides a completed anastomosisof the distal end of conduit 530 to coronary artery 20. FIG. 19 showsthe condition of the apparatus at this stage in the procedure.

[0094] The next step is to continue to proximally withdraw delivery tube540 until the proximal end of conduit 530 and proximal ring 520 b are nolonger inside tube 540 (see FIG. 21). Then proximal balloon 512 b isinflated to circumferentially expand ring 520 b and thereby set prongs522 through conduit 530 into the surrounding portion of conduit 430 andaorta wall portion 34 (see FIG. 22). This provides a completedanastomosis of the proximal end of conduit 530 to aorta 30.

[0095] The next step is to deflate balloons 512 a and 512 b andproximally withdraw tube 510 and delivery tube 540 from the patient viacatheter 210. Then wire 150 is withdrawn from the patient, either bypulling it proximally from catheter 210 or by pulling it proximally fromelements 110 and 120. Lastly, elements 110, 120, and 210 are allproximally withdrawn from the patient to conclude the procedure. Thebypass that is left in the patient is as shown in FIG. 23. This bypassextends from aorta 30 at location 34 to coronary artery 20 at location24. The bypass includes natural body conduit 530 inside artificial graftconduit 430. One end of the bypass is anchored and anastomosed tocoronary artery 20 by prongs 436 and ring 520 a. The other end of thebypass is anchored and anastomosed to aorta 30 by flaps 438 and ring 520b.

[0096] The particular uses of the invention that have been described indetail above are only illustrative of many possible uses of theinvention. Other examples include same-vessel bypasses in the coronaryarea and vessel-to-vessel and same-vessel bypasses in other portions ofthe circulatory system (including neurological areas, renal areas,urological areas, gynecological areas, and peripheral areas generally).A same-vessel bypass is a bypass that extends from one portion of avessel to another axially spaced portion of the same vessel. In FIG. 24,bypass 620 is a same-vessel bypass around a narrowing 612 in vessel 610.For ease of comparison to previously described embodiments, the variouscomponents of bypass 620 are identified using the same reference numbersthat are used for similar elements in FIG. 23. The invention is alsoapplicable to procedures similar to any of those mentioned above, butfor non-circulatory systems such as urological tubing.

[0097] Another illustrative alternative embodiment of some of theinstrumentation shown in FIG. 7 is shown in FIGS. 25 and 26. Tofacilitate comparison to FIG. 7, FIGS. 25 and 26 use reference numberswith primes for elements that are generally similar to elementsidentified by the corresponding unprimed reference numbers in FIG. 7.Each axial end portion of graft 430 includes a radially enlargeableconnector structure 449. Connector structures 449 may have any of alarge number of constructions. For example, each connector structure 449may include one or more annularly compressible, serpentine-shaped, metalrings 448 (e.g., of nitinol). When such a ring is annularly compressed,the serpentine convolutions of the ring become more sharply curved andcloser together. When such a ring is released to return to a more nearlyrelaxed state, the convolutions of the ring become somewhat straighter.If graft 450 is made of a metal (e.g., nitinol) framework 432 with acovering 434 (e.g., of silicone), rings 448 may be integral withframework 432, and covering 434 may continue into the vicinity of rings448. Rings 448 may be formed to hold struts 436′ substantially uniformlyout against the inner surface of body tubing all the way around thecircumference of the graft.

[0098] A particularly preferred way of producing a serpentine ring 448is to start with a short length of thin-walled metal tubing 460 as shownin FIG. 28 and cut away interdigitated portions 462 from opposite axialends of the tube as shown in FIG. 29. A typical thickness of tubing 460is approximately 0.003 to 0.006 inches, and a typical width of metalleft between adjacent slots 462 is about 0.008 inches. Slots 462 may becut in tubing 460 using a laser. The structure shown in FIG. 29 is thenradially enlarged and annealed. In its radially enlarged form, thestructure has the general appearance shown in FIG. 27 when viewed froman axial end. Each point 458 is adjacent an axial end of the originaltube 460. The structure can be resiliently radially compressed to thesize of the original tube 460 or an even smaller size, and it willreturn to the radially enlarged size and shape whenever released fromradial compression. Points 458 form radially outwardly extending highspots or raised portions that help ring 448 securely engage surroundingbody tissue by locally projecting to a greater extent into the tissue,even though points 458 may not actually penetrate the tissue.

[0099] As an alternative or addition to reliance on a ring like 448 toresiliently (elastically) self-expand to the full circumferential sizedesired in a completed graft connection, some or all of the desiredcircumferential expansion of such a ring may be produced by inflatingballoon 422′ or using another selectively radially enlargeable structureinside the ring to plastically deform the ring.

[0100] For use in a connector structure that includes struts like 436′,each strut may be connected (e.g., welded) to a peak of the serpentinestructure as shown for example in FIG. 29a. This may be done at anyconvenient time (e.g., before circumferential expansion of the FIG. 29structure).

[0101] It will be noted that a ring 448 made as described above inconnection with FIGS. 27-29 a may be somewhat ribbon-like (e.g., becausethe width of the metal between slots 462 is greater than the thicknessof that metal). Thus when the structure shown in FIG. 29 or 29 a iscircumferentially enlarged, the material in the peaks 458 of theconvolutions tends to twist. This can give these peaks a shape which isespecially effective in engaging adjacent body tissue. If struts like436′ are attached to these peaks as shown in FIG. 29a, the twisting ofthe peak material can be used to similarly twist the struts (e.g., tobias them in favor of radial outward projection and/or to rotate themabout their longitudinal axes to properly orient hooks and/or barbs onthem).

[0102] In the embodiment shown in FIGS. 25 and 26 struts 436′ areconnected to the distal end of the serpentine ring 448 of the connector449, which is connected in turn to the distal end of frame 432′. Struts436′ are initially held in the form of a distally pointed cone byyieldable bands 437 a, 437 b, 437 c, and 437 d. As elsewhere along graftconduit 430′, the spaces between struts 436′ are substantially filled bya highly elastic material such as silicone rubber. Bands 437 may be madeof a polymeric or other suitable yieldable material. Alternatively,bands 437 could be serpentine metal members that yield by becomingstraighter. Bands 437 are initially strong enough to prevent struts 436′from flaring radially outward from conduit 430′ as the struts areresiliently biased to do. However, bands 437 can be made to yield byinflating balloon 422′ (on the distal end of tube 420′) inside theannulus of struts 436′.

[0103] Struts 436′ can be forced through tissue such as the wall ofcoronary artery 20 in their initial cone shape. Sufficient pushing forcecan be applied to the cone of struts 436′ in any of several ways. Forexample, tube 420′ may be metal (e.g., stainless steel) hypotube whichcan transmit pushing force to the cone of struts 436′ by inflatingballoon 422′ to trap the base of the cone between balloon 422′ and tube440. Additional pushing force may then also be applied via tube 440itself.

[0104] When a sufficient portion of the height of the cone of struts436′ is through the coronary artery wall, balloon 422′ is inflatedinside the cone as shown in FIG. 26 to cause bands 437 to yield. Thisallows struts 436′ to flare radially outward inside the coronary artery,thereby anchoring the distal end of conduit 430′ to the artery. Bands437 may be made progressively weaker in the distal direction tofacilitate prompt yielding of distal bands such as 437 aand 437 b inresponse to relatively little inflation of balloon 422′, whereas moreproximal bands such as 437 c and 437 d do not yield until somewhat laterin response to greater inflation of balloon 422′. This progression ofyielding may help ensure that the annulus of barbs flares out in thedesired trumpet-bell shape inside the coronary artery.

[0105] As shown in FIG. 26a, in another embodiment struts 436′ areinitially held in the form of a distally pointed cone by a yieldablecone 441 which is attached to or is part of tube 440. Cone 441 may bemade of a polymeric or other suitable yieldable material. Cone 441 isinitially strong enough to prevent struts 436′ from flaring radiallyoutward from conduit 430′ as the struts 436′ are resiliently biased todo. However, cone 441 can be made to yield by inflating balloon 422′ (onthe distal end of tube 420′) inside the annulus of struts 436′. Struts436′ can be forced through tissue such as the wall of coronary artery 20in their initial cone shape. Sufficient pushing force can be applied tothe cone of struts 436′ in any of several ways. For example, tube 420′may be metal (e.g., stainless steel) hypotube which can transmit pushingforce to the cone of struts 436′ by inflating balloon 422′ to trap thebase of the cone between balloon 422′ and tube 440. Additional pushingforce may then also be applied via tube 440 itself.

[0106] When a sufficient portion of the height of the cone of struts436′ is through the coronary artery wall, balloon 422′ is inflatedinside the cone as shown in FIG. 26a to cause cone 441 to yield. Thisallows struts 436′ to flare radially outward inside the coronary artery,thereby anchoring the distal end of conduit 430′ to the artery. Cone 441may be made progressively weaker in the distal direction to facilitateprompt yielding of distal end in response to relatively little inflationof balloon 422′, whereas the more proximal end does not yield untilsomewhat later in response to greater inflation of balloon 422′. Thisprogression of yielding may help ensure that the annulus of struts 436′flares out in the desired trumpet-bell shape inside the coronary artery.The cone 441 may be withdrawn with the tube 440, and may even be madepart of tube 440.

[0107]FIG. 26b depicts tube 440 and cone 441 by themselves in order tobetter show that cone 441 may have a weakened zone 441 a extending inthe distal direction to help the cone yield to deploy struts 436′ whenballoon 422′ is inflated. Weakened zone 441 a can be a slit, a scoreline, a perforation line or any other generally similar structuralfeature.

[0108] Still another illustrative alternative embodiment of some of theinstrumentation shown in FIG. 7 is shown in FIG. 30. To facilitatecomparison to FIG. 7, FIG. 30 uses reference numbers with double primesfor elements that are generally similar to elements identified by thecorresponding unprimed reference numbers in FIG. 7. In the embodimentshown in FIG. 30, the distal end of artificial graft conduit 430″ isattached to expandable ring 448. Elongated struts 436″ extend distallyfrom the distal end of ring 448. The distal ends of struts 436″ areturned back in the proximal direction and extend just far enough intothe distal end of tube 420″ to be releasably retained by that tube.Struts 436″ are resiliently biased to extend radially outward from ring448, but are initially restrained from doing so by the presence of theirdistal end portions in the distal end of tube 420″. Thus struts 436″initially form a distally pointing cone that can be pushed throughtissue such as the wall of coronary artery 20 in the same manner thathas been described above in connection with FIGS. 25 and 26. Structure420″, which may be metal (e.g., stainless steel) hypotube with aninflatable annular balloon 422″ near its distal end, may be used to helppush the cone through the tissue.

[0109] After the distal portion of the cone of struts 436″ has beenpushed through the wall of coronary artery 20, tube 420″ is shiftedproximally relative to the struts 436″ to release the distal endportions of the barbs. This allows struts 436″ to spring radiallyoutward from ring 448 inside coronary artery 20, thereby anchoring thedistal end of the graft conduit in the coronary artery. Ring 448 canthen be circumferentially expanded to increase the size of theconnection between coronary artery 20 and the distal portion of thegraft conduit. If desired, each of struts 436″ may be twisted 180°before it enters the distal end of tube 420″. This promotes turning ofthe hook-like extreme distal end portions of the struts toward thecoronary artery wall when the struts are released from tube 420″.

[0110] Ring 448 and struts 436″ may be made of any suitable materialsuch as any 300-series stainless steel (e.g., 316L stainless steel).Another material that may be suitable for struts 436″ is nitinol. As inpreviously described embodiments, the elastic cover 434 that forms partof conduit 430″preferably extends to regions 430 a and 436″.

[0111] In FIG. 30, the struts 436″ are attached to ring 448 at theclosest (distal-most) points of the ring 448. This causes the struts436″ to pull in the proximal direction when the ring 448 is expanded byballoon 422″. This causes the hooks on the ends of the struts to pullinto the surrounding tissue for a more secure attachment. The hooks onthe ends of struts 436″ may also have barbs formed thereon for an evenmore secure attachment to body tissue.

[0112] As shown in FIG. 30a, there may also be outer struts 435 whichare attached to the farthest (proximal-most) points of the ring 448 andto a band 433 at their distal ends. When the ring 448 expands, the outerstruts 435 are pushed in the distal direction, which causes band 433 tomove distally, and therefore closer to the artery wall to help sealagainst the artery wall. In other words, the body tissue is trappedbetween radially outwardly extending struts 436″ on the inside of thetissue wall and band 433 on the outside of the tissue wall.Circumferential expansion of ring 448 and consequent proximal motion ofbarbs 436″ and distal motion of band 433 apply compressive stress to thetissue wall between those inner and outer portions of the connector.

[0113] Still another illustrative alternative embodiment of some of theinstrumentation shown in FIG. 7 is shown in FIG. 31. In the embodimentshown in FIG. 31, the distal end of artificial graft conduit 430 isattached to expandable ring 448. Elongated struts 436 extend distallyfrom the distal end of ring 448. The distal ends of struts 436 havehooks 466 having small barbs 467 at the ends. The struts 436 are turnedback in the proximal direction. Struts 436 are resiliently biased toextend radially outward from ring 448, but they are initially restrainedfrom doing so by the presence of their distal end portions wrapped by arestraining wire 465. Thus struts 436 initially form a distally pointingcone that can be pushed through tissue such as the wall of coronaryartery 20 in the same manner that has been described above. The wire465, which may be metal (e.g., stainless steel), is then pulled backproximally to unwrap the distal portion from around the struts. Thisallows struts 436 to spring radially outwardly from ring 448 insidecoronary artery 20, thereby anchoring the distal end of the graftconduit in the coronary artery using the hooks 466 and barbs 467. Ring448 can be circumferentially expanded at any suitable time to increasethe size of the connection between coronary artery 20 and the distalportion of the graft conduit 430.

[0114]FIG. 32 shows a variation of the FIG. 31 apparatus. In the FIG. 32variation, struts 436″are initially restrained by a loop or coil on thedistal end of wire 465″. Wire 465″ extends distally from a lumen in thewall of tube 420. When it is desired to release struts 436″ to extendradially outwardly, tube 420 is rotated about its central longitudinalaxis. This rotates the loop or coil in wire 465″, thereby releasingstruts 436″ one after another. After all of struts 436″ have beenreleased from the wire loop, wire 465″ may be proximally retractedrelative to tube 420 so that the loop in wire 465″ is adjacent thedistal end of that tube. Alternatively, wire 465″ may be proximallyretracted all the way into the lumen in the wall of tube 420 from whichthe wire initially extends.

[0115] An alternative construction of the proximal end of artificialgraft conduit 430 is shown in FIG. 33. The embodiment shown in FIG. 33can be used with any construction of the distal end of conduit 430, butFIG. 33 assumes that the depicted proximal end construction is used witha distal end construction of any of the types shown in FIGS. 25-26 a and30-32.

[0116] In the embodiment shown in FIG. 33 the proximal end of conduit430 has a plurality of struts 1436 that are resiliently biased to extendradially out from the remainder of the conduit. Initially, however,struts 1436 are confined within delivery tube 440 as shown in FIG. 33.Like distal struts 436, struts 1436 may be proximal extensions of theframe 432 of conduit 430, or they may extend proximally from a ring ator near the proximal end of conduit 430. This proximal ring may besimilar to distal ring 448 described above in connection with FIGS. likeFIG. 25. The covering 434 of conduit 430 may extend to all, part, ornone of the length of struts 1436. Struts 1436 may include resilienthooks, and the free end portions of struts 1436 or the hooks on thosestruts may include barbs. Representative struts 1436, each with a hook1466 and a barb 1467, are shown after deployment and in more detail inFIG. 34. This FIG. shows that struts 1436 flare out inside aorta 30 andthat the free ends of hooks 1466 penetrate the aorta wall tissue shownat 34. Barbs 1467 engage the tissue like fish hook barbs to resist anytendency of hooks 1466 to pull out of the tissue.

[0117] The proximal end of conduit 430 is attached to the wall of aorta30 (after attachment of the distal end to coronary artery 20 asdescribed above in connection with numerous other FIGS.) by proximallyretracting delivery tube 440 so that struts 1436 can spring out againstthe inside of catheter 210 in the vicinity of proximal balloon 212. Thendistal balloon 214 is deflated and catheter 210 is retracted proximallyso that struts 1436 can spring out against the inside surface of thewall of aorta 30 as is generally shown in FIG. 34. If provided, hooks1466 and barbs 1467 penetrate the aorta tissue as shown in FIG. 34.

[0118] As part of the procedure for connecting the proximal end ofconduit 430 to the aorta, it may be desirable to proximally retract theballoon 422/422′/422″ (described above in connection with numerous otherFIGS.) to the proximal end of conduit 430 and to there re-inflate theballoon to help hold conduit 430 in place before proximally retractingdelivery tube 440. The balloon can be deflated again at any suitabletime (e.g., after delivery tube 440 has been proximally retracted).Balloon 422/422′/422″ may additionally or alternatively be inflatedduring proximal retraction of catheter 210. This may help ensure thatstruts 1436 are fully and properly deployed and that the connection ofconduit 430 to aorta 30 is properly molded. If a ring similar to ring448 is part of the proximal conduit connection, inflation of balloon422/422′/4221″ may be used to circumferentially expand that ring as partof the process of connecting conduit 430 to the aorta.

[0119] Possible refinements of a proximal connector of the general typeshown in FIGS. 33 and 34 are shown in FIGS. 34a and 34 b. (The structureshown in FIGS. 34a and 34 b can also be used as a distal connector.)FIGS. 34a and 34 b show the connector fully installed though an aperturein body tissue wall 34. Artificial graft conduit 430 is formed so thatits proximal portion is resiliently biased to assume the shape shown inFIGS. 34a and 34 b. In particular, this shape includes a medial,radially outwardly projecting, annular flange 430 a, and a proximal,radially outwardly projecting, annular flap 430 b. Flange 430 a isintended to be deployed outside body tissue wall 34 as shown in FIG.34a, while flap 34 b is intended to be deployed inside the body tissuewall. In addition, a connector 449 (similar to the connectors 449 inearlier-described FIGS. such as FIGS. 25-30, 31, and 32) is providedadjacent flap 430 b. Connector 449 includes a radially expandableserpentine ring 448 and a plurality of struts 436 which are resilientlybiased to project radially outwardly. In this embodiment struts 436 passthrough the structure of flap 430 b to help push the flap up inside andagainst the inner surface of tissue wall 34.

[0120] As in previous embodiments, the structure shown in FIGS. 34a and34 b may be delivered to the intended location in the body inside adelivery tube (e.g., like tube 440 in FIG. 33). While the structure isinside the delivery tube, all of elements 430 a, 430 b, and 436 areconstrained by that tube into a substantially tubular shape. When thedelivery tube is proximally retracted from conduit 430, elements 430 a,430 b, and 436 resiliently return to the shapes shown in FIGS. 34a and34 b, thereby making a secure and fluid tight connection between theproximal end of conduit 430 and body tissue wall 34.

[0121]FIG. 35 illustrates another possible use of the connectingstructures as described above, as well as illustrating other possibleaspects of the invention. FIG. 35 illustrates a structure that can beused to deliver an artificial graft conduit, or a natural graft conduit,or both an artificial graft conduit and a natural graft conduitsimultaneously (e.g., with the natural conduit coaxially inside theartificial conduit). In the particular case shown in FIG. 35 it isassumed that only natural graft conduit is being delivered, but it willbe readily apparent that artificial graft conduit could be substitutedfor or added outside the natural graft conduit.

[0122] In the embodiment shown in FIG. 35 the cone of struts 436′ isattached to the distal end of a natural graft conduit 530. The proximalend of natural graft conduit 530 is attached to ring 461. The cone ofstruts 436′ is provided with relatively short, radially outwardlyprojecting prongs 433. Prongs 433 extend into and/or through the distalportion of the length of graft tubing 530, which (as has been mentioned)is assumed in this case to be natural body organ tubing such assaphenous vein. Ring 461 is similarly provided with radially outwardlyextending prongs 462, which extend into and/or through the proximalportion of graft conduit 530. Ring 461 also includes resilient radiallyoutwardly extending annular flaps 438 a and 438 b with prongs 439, allsimilar to correspondingly numbered elements in FIG. 8. Structure 420′is disposed around wire 150 inside structures 436′, 450, 460, and 530.Delivery tube 440 is disposed around conduit 530.

[0123] The embodiment shown in FIG. 35 illustrates a structure which canbe used to deliver and install natural body organ conduit without anyfull length artificial graft conduit being used. In a manner similar towhat is shown in the previous FIGS., the structure shown in FIG. 35 isdelivered to the operative site via wire 150. The cone of struts 436′ isforced through the wall of coronary artery 20 and then flared radiallyoutward inside the coronary artery to anchor the distal end of the graftconduit to that artery. The distal end of delivery tube 440 is pulledback as needed to aid in attachment of the distal end of the graftstructure. Attachment of the proximal end of the graft structure to thewall of aorta 30 is performed similarly to what is shown in the aboveFIGS. Accordingly, with distal flap 438 a just outside the wall of aorta30, delivery tube 440 is pulled back proximally to expose that flap.Flap 438 a is thereby released to spring out and engage the outersurface of the aorta wall. After that has occurred, proximal flap 438 bis adjacent the inner surface of the aorta wall. Tube 440 is pulled backproximally even farther to expose flap 438 b so that it can spring outand engage the inner surface of the aorta wall. Natural body organ graft530 is now fully installed in the patient. Struts 436′, 450, and 460remain in place in the patient to help anchor the ends of graft conduit530 and to help hold open the medial portion of that conduit.

[0124]FIG. 36 shows an alternative to what is shown in FIG. 35. In FIG.36 a distal annular connector structure 449 a is annularly attached tothe distal end of conduit 530 (similar to conduit 530 in FIG. 35), and aproximal annular connector structure 449 b is annularly attached to theproximal end of conduit 530. For example, each of connectors 449 may besutured to the respective end of conduit 530. In that case connectors449 may be inside or outside conduit 530. Each of connectors 449 may besimilar to the connectors 449 in earlier-described FIGS. such as FIGS.25-30, 31, and 32. Thus, each of connectors 449 includes a serpentinering 448 with a plurality of struts 436 extending from the ring. Withthis construction, as an addition or alternative to suturing eachconnector 449 to conduit 530, the ring 448 of each connector may beinside the conduit and the high spots 458 (FIG. 27) on the ring may beused to dig into the tissue of conduit 530 (without actually penetratingthe tissue) to secure or help secure the connector to the tissue.

[0125] The struts 436 a of distal connector 449 a extend in the distaldirection from ring 448 a and are initially restrained into a cone shapeby a release wire 465 as shown in FIG. 31. The struts 436 b of proximalconnector 449 b extend in the proximal direction from ring 448 b and areinitially constrained by being inside delivery tube 440. The struts 436a of distal connector 448 a are deployed to spring radially outwardlyand engage body tissue by proximally retracting release wire 465. Thestruts 436 b of proximal connector 448 b are deployed to spring radiallyoutwardly and engage body tissue by proximally retracting delivery tube440. The structure shown in FIG. 36 can be used in any of the ways thatare described above for the structure shown in FIG. 35.

[0126]FIG. 37 shows a structure that may be used as an alternative tothe embodiments described above. For example, structures like this maybe used in place of the connectors using barbs, or wherever else agenerally similar connecting structure is needed. A T-flange connector700 is provided. It is constructed generally similar to the graftconduits 430 described above, having a frame, and a covering. Theconnector 700 is formed in the shape of a “T” of hollow tubular sectionsand is resiliently biased to return to this shape. The connector isinitially deployed with one of the ends 702 of the top of the “T”inverted or compressed into the other end 704 of the top of the “T” asshown in FIG. 38. The compressed connector is then deployed using a tube440 as described above. Once the tube 440 is withdrawn, the connector700 expands to its original “T” shape. For example, the top of the “T”may be inserted into coronary artery 20 through an aperture in the sidewall of that artery as shown in FIG. 39. After insertion, one leg 704 ofthe top of the “T” extends upstream along the coronary artery, and theother leg 702 extends downstream along that artery as shown in FIG. 40.The remainder of the “T” (i.e., the “vertical” portion of the “T”)extends out of the aperture in the coronary artery so that the base ofthe “T” can be connected to the aorta (e.g., using any of the otherconnector structures and techniques described above). The fact that thetop of the “T” extends both upstream and downstream along the coronaryartery anchors the graft to the coronary artery.

[0127] As used herein, references to a patient′s existing body organtubing or the like include both natural and previously installed grafttubing (whether natural, artificial, or both). The artificial grafts ofthis invention may be coated (in the case of tubular grafts, on theinside and/or outside) to still further enhance their bio-utility.Examples of suitable coatings are medicated coatings, hydrophyliccoatings, smoothing coatings, collagen coatings, human cell seedingcoatings, etc. The above-described preferred porosity of the graftcovering helps the graft to retain these coatings. Additional advantagesof the artificial grafts of this invention are their elasticity anddistensibility, their ability to be deployed through tubes of smallerdiameter (after which they automatically return to their full diameter),the possibility of making them modular, their ability to accept naturalbody organ tubing concentrically inside themselves, their ability tosupport development of an endothelial layer, their compatibility withMRI procedures, their ability to be made fluoroscopically visible, etc.

[0128] It will be understood that the foregoing is only illustrative ofthe principles of the invention, and that various modifications can bemade by those skilled in the art without departing from the scope andspirit of the invention. For example, the order of some steps in theprocedures that have been described are not critical and can be changedif desired.

The invention claimed is
 1. A connector for use in connecting an axialend portion of a tubular medical graft to the side wall of a patient'stubular body tissue conduit so that the lumen of the graft communicateswith the lumen of the conduit through an aperture in the side wall ofthe conduit to permit body fluid flow between the lumens without leakageof body fluid to the outside of the graft and the conduit adjacent theconnector comprising: an annular structure having first and secondaxially adjacent substructures, the first substructure being configuredto be disposed substantially concentrically inside the axial end portionof the graft and being circumferentially enlargeable to press the axialend portion of the graft radially outwardly toward the body tissuesurrounding the aperture, and the second substructure including aplurality of struts that are configured to extend substantially radiallyoutwardly to engage the body tissue surrounding the aperture and holdthe axial end portion of the graft in body-fluid-tight engagement withthe side wall of the conduit annularly around the aperture, wherein thefirst substructure is resiliently biased to circumferentially enlarge toat least some degree by itself.
 2. The connector defined in claim 1wherein the annular structure comprises: a ring having convolutions thatrepeatedly traverse a circumference of the annular structure, the ringbeing circumferentially enlargeable by straightening out theconvolutions to some degree.
 3. The connector defined in claim 1 whereinthe struts are configured to extend through the annular portion of thegraft to engage surrounding body tissue.
 4. The connector defined inclaim 1 wherein the struts include hooks configured to penetratesurrounding body tissue.
 5. The connector defined in claim 1 wherein thestruts include barbs configured to penetrate surrounding body tissue andto resist withdrawal of the struts from the penetrated body tissue. 6.The connector defined in claim 1 wherein the struts are resilientlybiased to extend substantially radially outwardly to engage surroundingbody tissue, and wherein the struts are additionally configured toelastically deflect substantially parallel to an axis with which theannular structure is substantially coaxial.
 7. The connector defined inclaim 1 wherein the struts are resiliently biased to extendsubstantially radially outwardly to engage surrounding body tissue, andwherein the struts are additionally configured to elastically deflectsubstantially into a cone which has its apex on an axis about which theannular structure is substantially coaxial.
 8. The connector defined inclaim 1 wherein the annular structure is at least partly made ofnitinol.
 9. The connector defined in claim 1 wherein the annularstructure is at least partly made of stainless steel.
 10. The connectordefined in claim 3 wherein the ring is produced from a tube by removinginterdigitated portions from the tube, alternating removed portionsextending in from opposite ends of the tube.
 11. The connector definedin claim 10 wherein the tube has thickness less than the spacing betweenadjacent removed portions.
 12. The connector defined in claim 1 whereinthe annular structure further comprises: a tissue clamping structureconfigured to move toward the struts in response to circumferentialenlargement of the annular structure in order to clamp tissue betweenthe clamping structure and the struts.
 13. The connector defined inclaim 12 wherein the annular structure further comprises: a ring whichis serpentine along a circumference of the annular structure, the strutsbeing connected to the ring adjacent one axial end of the connector andthe tissue clamping structure being attached to the ring adjacent theother axial end of the connector so that when the ring iscircumferentially enlarged and the ring accordingly becomes lessserpentine, the struts and the tissue clamping structure move toward oneanother.
 14. The connector defined in claim 13 wherein the tissueclamping structure comprises: a second ring substantially parallel toand concentric with the first-mentioned ring.
 15. The connector definedin claim 14 wherein the tissue clamping structure comprises a pluralityof struts connecting the second ring to the first-mentioned ringadjacent said other axial end of the connector.
 16. The connectordefined in claim 6 further comprising: a tubular structure axiallyreciprocable relative to the connector into and out of a position inwhich the tubular structure is substantially concentric outside theannular structure and releasably holds the struts substantially parallelto the axis with which the annular structure is substantially coaxial.17. The connector defined in claim 7 further comprising: a yieldablestructure for releasably holding the struts in the cone.
 18. Theconnector defined in claim 17 wherein the yieldable structure comprises:a yieldable band around the struts.
 19. The connector defined in claim17 wherein the yieldable structure comprises: a yieldable cone over thestruts.
 20. The connector defined in claim 7 further comprising: aremovable member around the struts.
 21. The connector defined in claim20 wherein the removable member comprises: a wire wrapped around thestruts.
 22. The connector defined in claim 20 wherein the removablemember comprises: a coil around the struts configured to release thestruts when the coil is rotated about its central longitudinal axis. 23.The connector defined in claim 7 wherein each of the struts includes aninitially radially inwardly directed hook, and wherein the connectorfurther comprises: a removable member for releasably engaging the hooks.24. The connector defined in claim 1 wherein the annular structurefurther comprises: a multi-sided ring having a plurality of radiallyoutwardly pointing corners circumferentially spaced from one anotheraround the ring.